William w



(No Model.)

W. W. GRISCOM.

AUTOMATIC CIRCUIT CHANGER FOR SECONDARY BATTERIES. No. 391,468. Patented Oct. .23, 1888.

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(UNITED STATES 1 i 1, 'v' 1's FATENT le WILLIAM XV. GRISCOM, OF HAVERFORD COLLEGE, PENNSYLVANIA.

AUTOMATIC CIRCUIT=CHANGER FOP; SECGNDARY ATTERIES.

SPECIFICATION forming part of Letters Patent No. 391,468, dated October 23, 1888.

Application filed June 30. 1888.

To all whom it may concern.-

Be it known that 1, WILLIAM W. GRISCOM, a citizen of the United States, and a resident of Haverford College, in the county of Montgomcry and State of Pennsylvania, have invented certain new and useful Improvements in Automatic Circuit-Changers, ot'which the following is a specification.

My invention is an improvement in automatic circuit-changers for use with secondary batteries.

The object of my invention is to prevent too rapid a discharge in the working-circuit of a secondary battery, whereby the injurious effects resulting therefrom are avoided.

My invention comprises an electro-magnet located in the working-circuit, wound, arranged, and adjusted to respond to a predctei mined strength of current. There is an artificial resistance, for introduction with respect to the main circuit, which is normally excluded from the circuit by a switch-arm controlled by the electromagnet; but when the current is raised to a sufficient strength to operate the electro-magnet the artificial re sistance is introduced into the circuit, so that the lamps burn red, thus giving notice of too great a demand on the capacity of the battery. When the lamps are so reduced in number that the demand for current is again normal, the artificial resistance is again excluded by the action of the magnet and the remaining lamps are again raised to incandescenee.

The accompanying drawing illustrates my invention.

0 is a central station.

S and S are sub-stations connected with dynamo D at the central station by a main conductor, 1 2. At each sub-station is a series of cells of secondary battery BB. Each battery is provided with a working-circuit, it, containing translating devices, as lamps Z. Each working circuit 20 contains the coils of an electro-magnet, m, having an armature, a, fixed to a pivoted switch-arm, Z), carrying at its extremity a bent platinum wire, a.

c c are two mercury-cups, respectively forming the terminals of the divided working-circuit w. An artificial resistance, R, is permanently connected to points in the circuitw, on opposite sides of the mercury-cups. Normally the armature a is retracted and the wire a unites the mercury-cups.

Serial No. 27$,GST. (No model.)

The magnet in is wound and adjusted to re spond to a predetermined strength of current which is the normal safe discharge-rate of the size of battery-cel1 in use. \Vhen lamps Z are added in quantity sufficient to absorb current from the battery at a greater rate, the armature a is attracted, the wire a raised out ofthc cups 0 c, introducing resistance It. This causes a reduction in the strength of current to about the normal rate; but the armature a has been carried nearer to the magnet-cores, and being in a stronger magnetic field it is held in its new position until released by hand. The result of the insertion of this resistance is a decrease in the difference of potential at the lamp-terminals, which is noticeable in the color of the filament or in the operation of the translating device, whatever it may be, and the normal conditions are only restored when the excess of translating devices is disconnected.

It will thus be seen that by the use of my improved arrangement the danger of damage to the battery in an attempt to consume its energy too rapidly is avoided.

\Vhat I claim,and desire to secure by Letters Patent. is

1. The combination of a secondary battery, a working-circuit therefor,a switch or circuitchanger for making and breaking said circuit, and an electro magnet having its coils included in said circuit controlled by a predetermined strength of current to operate said switch or circuit-changer.

2. The combination of a secondary battery, a workingcircuit therefor,a switch or circuitchangcr for making and breaking said circuit, an artificial resistance connected to the main circuit upon opposite sides of the circuitbreaker, but normally excluded thereby, and an electro-magnct located in said circuitand controlled by a predetermined maximum strength of current to operate the said switch or circuit-changer.

Signed at New York, in the county of New York and State of New York, this 28th day of June, A. D. 1888.

V7. \V. GRTSCOM.

lVitnesses:

DANIEL E. DELAYAX, WM. 13. Vansrzn. 

